Unionicola (Mutelicola) blayi, Gledhill & Vidrine, 2002

Gledhill, Terence & Vidrine, Malcolm F., 2002, Two new sympatric water-mites (Acari: Hydrachnidia: Unionicolidae) from the mutelid bivalve Aspatharia sinuata (von Martens) in Nigeria with some data on unionicoline-bivalve relationships, Journal of Natural History 36 (11), pp. 1351-1381 : 1355-1361

Unionicola (Mutelicola) blayi new species

(gures 1–5)

Description of male (gures 1a–f, 2a–l, 3a–d). With the characters of the genus and subgenus. Body elongate and without a cauda; length excluding gnathosoma 878 (634–878, 720, n 55), width 598 (512–610, 563, n 55). Dorsum (gure 1a) with a single dorsal shield, length 498 (324–498, 385, n 55). Ventrally with epimera in four groups occupying ca half ventral surface and with anterior groups well separated from posterior groups; anterior groups with prominent posterolaterally-directe d apodemes; posterior groups with a well-de ned lateral cleft between Ep.3 and 4 and with more-or-less straight posterior margins to Ep.4 (gure 1b)—in some specimens the posterior margins appear straighter and more at right angles to the long axis of the body; Ep.4 with pointed lateral extensions at point of IV-Leg insertions (gure 1b); total epimeral length 504 (354–504, 409, n 55); median length Ep.31 4, 258 (198–258, 215, n 55); median length Ep.4, 180 (132–180, 148, n 55); epimeral width at Ep.3, 420 (414–450, 433, n 54); epimeral width at Ep.4, 468 (414–486, 461, n 54). Infracapitulum small, length 168 (156–192, 174, n 55); chelicerae short and stout, basal portion reticulate, length 192 (168–192, 186, n 55), cheliceral claw length (dorsal i.e. short length) 39 (36–42, 39, n 55). Pedipalps as in gures 1d–f, 2a–i; P.II with a proximal spine-like seta on outer lateral face and a dorsodistal spine on inner lateral face; P.III with a long ventrodistal hair-like seta on outer lateral face and a shorter pectinate seta distally on inner lateral face; P.IV with two short hair-like setae on outer lateral face and a short ventrodistal projection bearing two ne setae. P.V ventrally concave and distally multitoothed (gures 1e, 2g, i). Lengths of pedipalp segments: P.I, 18 (15–18, 18, n 59); P.II, 123 (108–126, 119, n 59); P.III, 90 (78–90, 85, n 59); P.IV, 132 (108–132, 124, n 510); P.V, 84 (66–84, 78, n 510). Genital eld at posterior end of body, terminal and almost dorsal (holotype, male, Prep. 1360, tilted to show genital eld as depicted in gure 1b). Genital eld (gures 1c, 2j, k, l) comprised of two pairs of genital plates; anterior plates each with two to ve or more (generally three) acetabula; setae-bearing portion of anterior genital plates may be separate from acetabula-bearing portion (gure 2j); posterior plates larger than anterior plates and each with 9–14 acetabula; gonopore slit-like and anked on each side by two adjacently-located long setae; genital eld length 123 (123–144, 134, n 54), genital eld width 153 (123–156, 145, n 55). Excretory pore slit-like, free in posterior integument and dorsal to posterior genital sclerite. Morphology and chaetotaxy of legs as illustrated in gure 3a–d. I-Leg.4–5 (genu and tibia) more-or-less equal. Segment 5 (tibia) of all legs, particularly I-Leg.5, convex dorsally in lateral view, more obvious than shown in gure 3a–d. All legs, particularly III and IV, with numerous hair-like setae. Claws of all legs with two distal teeth, ventral tooth ca twice length of dorsal tooth and with a small pre-distal lateral accessory tooth. Lengths of leg segments: I-Leg.1–6: 66 (60–72, 67, n 56), 90 (72–96, 86, n 59), 132 (102–132, 124, n 510), 186 (150–192, 175, n 510), 186 (150–192, 174, n 510), 123 (90–126, 113, n 510); II-Leg.1 –6:— (66, n 51), 105 (78–108, 100, n 58), 156 (120–156, 147, n 59), 210 (162–216, 200, n 59), 228 (174–228, 213, n 59), 162 (138–162, 149, n 59); III-Leg.1–6: 72 (66–72, 70, n 53), 108 (84–108, 99, n 59), 159 (120–162, 144, n 59), 213 (168–222, 201, n 59), 251 (180–252, 228, n 59), 186 (126–186, 165, n 58); IV-Leg.1–6: 120 (114–138, 127, n 54), 114 (78–120, 105, n 58), 198 (150–198, 181, n 58), 258 (198–264, 238, n 58), 336 (252–342, 308, n 57), 252 (192–252, 228, n 57).

Female (gures 4a–g, 5a–d). Body rounder and larger than that of male; length, excluding gnathosoma, 1075 (1025–1171, 1110, n 54), width 756 (756–915, 845, n 54). Dorsum (gure 4a) without a dorsal shield but with two pairs of muscle attachment sites. Ventrally with epimera in four groups occupying ca half ventral surface (gure 4b), anterior groups well separated from each other and from posterior groups and with prominent posterolaterally-directe d apodemes; lateral cleft between Ep.3 and 4 well de ned; posterior margin of Ep.4 more-or-less straight as in male; Ep.4 with pointed lateral extensions at point of IV-Leg insertions; epimeral groups of each side further apart from each other than in male, this separation may be less in immature females; total epimeral length 522 (408–522, 484, n 55), median length Ep.31 4, 258 (240–258, 251, n 54), median length Ep.4, 186 (180–192, 186, n 54); epimeral width at Ep.3, 552 (486–634, 572, n 55), epimeral width at Ep.4, 658 (612–744, 679, n 55). Infracapitulum and chelicerae as in male, infracapitulum length 174 (162–190, 175, n 53), chelicera length 204 (174–204, 189, n 52), cheliceral claw length (dorsal, i.e. short length) 42 (n 51). Pedipalps (gures 4c, d, 5b, d) similar to those of male, lengths of pedipalp segments: P.I, 18 (18–24, 20, n 58); P.II, 132 (126–144, 135, n 56); P.III, 118 (102–120, 112, n 56); P.IV, 138 (138–162, 149, n 56); P.V, 87 (84–90, 89, n 55). Genital eld (gures 4b, e, f, g; 5b, d) terminal (allotype female, Prep. 1361; female, Prep. 1375; female, Prep. 1364, tilted to show genital eld as depicted in gures 4b, e, 5c, respectively); gure 4f, g depict genital eld (Prep. 1375) in ventral and lateral aspects, respectively, drawn prior to nal microscope preparation. Genital eld consisting of two pairs of somewhat rectangular-shaped genital plates; anterior (ventral) genital plates each with three to four laterally sited acetabula, anteromedially with three short setae and posteromedially with two long setae on a strongly sclerotized projection; posterior (dorsal) genital plates each with 9–12 laterally-sited acetabula, anteromedially, i.e. when viewed as in gures 4e, 5c, with a single long stout seta, a few short setae associated with the acetabula; gonopore slit-like; genital eld length 210 (198–228, 212, n 53), genital eld width 252 (222–270, 250, n 55). Excretory pore slit-like, free in posterior integument and dorsal to posterior genital sclerite. Morphology and chaetotaxy of legs as illustrated for male. Lengths of leg segments: I-Leg.1–6:—(72–78, 75, n 52), 93 (90–108, 103, n 58), 141 (138–150, 147, n 58), 198 (192–216, 210, n 58), 189 (186–216, 205, n 58), 120 (120–126, 122, n 58); II-Leg.1–6:—(72, n 51), 117 (114–126, 120, n 57), 168 (168–186, 177, n 57), 231 (228–264, 246, n 57), 249 (246–282, 265, n 57), 168 (162–174, 169, n 57); III-Leg.1–7: 78 (78–90, 84, n 54), 114 (108–126, 123, n 58), 174 (174–192, 185, n 58), 243 (240–276, 261, n 57), 264 (252–306, 290, n 57), 198 (186–198, 194, n 56); IV-Leg.1–6: 138 (138–162, 148, n 55), 132 (132–150, 143, n 58), 231 (228–252, 244, n 58), 303 (300–336, 319, n 58), 366 (366–408, 391, n 58), 261 (258–282, 268, n 58)

Material examined. Five males: holotype, Prep. 1360; paratypes, Preps 1356, 1357, 1358 and 1359; ve females: allotype, Prep. 1361; paratypes, Preps 1362, 1363, 1364 and 1375. All material collected by Prof. John Blay from Asa Reservoir, Ilorin, Nigeria, no date supplied but shortly after April 1983 (personal communication) .

Etymology. The species is named for Prof. John Blay Jr who collected and sent this material to T.G.